Hypodermic stringe



Sept. 7, 1937.

R. K. CUTTER HYPODERMIC summer:

ori inal Filed July 21". 1.930

. INVENTOR. Wok 16m n An ye'ifi a m NRQKW;

Reissued Sept, 1, i931 UNITED STATES PATENT OFFICE monaamc sr'nmos Robert K. Cutter, Berkeley, Calif.,-assignor to Cutter Laboratories, Berkeley, Calif., a corporation of California Original No. 1,948,982, dated February; 27, 1934, Serial No. 628,790, August 15, 1932, which is a continuation of application July 21, 1930, Serial No. 469,447. This application for reissue February 3, 1936. Serial No. 62,162

2 Claims.

This application is a continuation of my application Serial No. 469,447, filed July 21, 1930, for 'Hypodermic syringe."

This invention relates to improvements in the construction of hypodermic syringes particularly designed for use in connection with the storage, transportation, preservation andapplication of biological and similar products which are stored,

transported, preserved or dispensed in syringe containers.

Objects of the present invention are generally to improve and simplify the construction and op eration of devices of the character described; to provide a syringe charged with the medicine to be injected and which may function as a storage container butnot' permit leakage of the medicine from the front to the rear of the plunger even,

when subjected to vibration such as occurs dur-' ing transit; to provide an improved type of piston or plunger which will not permit leakage from the front to the back thereof; to provide an imthe appended description taken in connection with the accompanying drawing which illustrates the invention. In such drawing- Figure 1 is a central longitudinal section in which is inserted a rubber sealing plug 3 and this is in turn designed .to receive a hollow needle 4 throughwhich the serum is discharged.

The opposite end ofthe cylinder or barrel is open and provided with a flange I and this is protected by means of an annular rubber ring 6 which functions as a finger grip. Adapted to be inserted in the cylinder or barrel A is a combination plunger and sealing plug generally indicated at B and for suitable attachment thereto I provide an operating handle I. The plunger consists of a head member I, one end of which terminates in a shank-like extension 9 which is adapted to receive the operating handle. The periphery of the head terminates in an annular flange or ring II) which forms the contact member of the plunger, and the exterior surface ll of this member forms a snug fit with relation to the inner surface of the barrel. The head memw ber 8 also carries a plug or filler member I! and there is an annular groove or space l3 formed between said plug and contact ring ill to permit free expansion and contraction thereof. The

annular groove I! should be of substantially greater depth than the contacting surface ll, while the width of this groove may be suflicient to admit liquid so that a pressure will be exerted on the walls thereof when forward movement is imparted to the plunger during discharge of the medicine; while that part III comprised between the annular groove l3 and the exterior surface ll (taken on a cross section) should be of surficient thickness to make and maintain a good contact with the inner surface of the barrel in I order to prevent suflicient yielding a permit passage of liquid from ahead of the plunger to points therebehind, such thickness being determined with a consideration of the softness and flexibility and possibly other characteristics of the material of which the plunger is made. This part between the annular groove l3 and the outer periphery is so made that it normally tends to have an outer periphery slightly greater than the inner periphery of the barrel. The projection I4 serves only to reduce the residual syringe contents to a minimum and is here shaped to fit the syringe neck as closely as possible. It will, of course, be modified in shape to fit the neck of any syringe and it can be entirely eliminated, if desired,'in which case a depression or well is formed within the annularcontact ring In.

The plunger as a whole will preferably be constructed of soft rubber or a similar material and in actual operation it will be inserted in the open end of the barrel after the barrel has been sterilized. The barrelis then filled with serum through the neck and the plug prevents escape,

for the saving of human life, but it often happens that a physician will carry necessary products for many miles tothe patient only to find that on arrival a substantial part of the medicine has tween the flller plug i2 and the contact ring I0,

an outward pressure is exerted on the inner face of the contact ring, thus forcing the contact face I I into snug engagement with the inner surface of the barrel and insuring complete discharge of the serum content.

Furthermore, when the plunger is forced inwardly by means of the operating handle the plunger as a whole tends to slightly compress due to frictional resistance and this compressing 1 action further assists in maintaining a snug engagement between the plunger and the barrel. While the plunger mechanism illustrated in this instance is primarily intended for antitoxin syringes which are filled with a single charge and a which are discarded after first use, it is obvious that the plunger may be employed in connection with permanent syringes and like devices. In

that case the shank or extension 9 may be provided with molded threads or the like so that it may be readily connected with a rodor any other plunger operating mechanism of suitable construction.

In actual practice, theannular ring in of the plunger is sufficiently resilient to expand by com-i pression, friction and by the application of pressure, while due to its resiliency it may be contracted or forced inwardly when inserted into a 4 barrel, while said part I! is sufficiently strong to maintain a position against the inner surface of the barrel which will prevent rearward movement of the medicine therepast. A plunger thus constructed permits a greater tolerance between the plunger and-the inner surface of the barrel than is usually possible with ordinary plungers. The plunger structure, accordingly, has several advantages, to-wit, it will function both as a plunger and as a'sealing plug. Due to the tolso erance permitted, it will fit a greater number of cylinders of varying size with less tendency to leakage or sticking. It is contractible and it is also automatically expansible when pressure or friction is applied and, as it is constructed of 5 rubber, it may be molded or otherwise formed. It will be observed that no matter where a cross section is taken on the head of my novel plunger, it will comprise space free from plunger material. w I prefer that the groove I! have a depth which is substantially twice the length of the contact surface II with the inner wall of the barrel and that the-sealing plug and plunger B be made entirely of soft flexible rubber, but these specific features are not necessarily limitations'of my invention. It is to be noted that it is not essential nor even very important that the pressure exerted by the liquid on moving the plunger forward in the syringe should be the cause of contact between the surface ll of the plunger head and the inside surface of the barrel: but what is important in my'invention is that the annular ring ll including the distal part II must be thick enough and strong enough to prevent a tendency to curl backward'when the fluid is being expelled from the syringe and to exert sufllcient force against the inside wall of the-barrel to prevent leakage while the fluid in the syringe V is being expelled therefrom or during jarring in transportation, and such thickness and strength will, of course, be dependent upon the resilience and other physical characteristics of the material of which the plunger is made which'is preferably rubber. This is important since a jar which might exert no pressure on the fluid, say a jar from the side, and which consequently would have little or no effect on keeping the annular contact surface ll against the inside wall of the barrel, would tend to have quite the opposite effect, namely, to make a break or opening so that fluid could leak from the front to the back of the plunger.

While certain features of the present invention are more or less specifically described, I wish it understood that various changes may be resorted to within the scope of the appended claims; similarly, that the materials and finishes of the several parts employed may be such as the manufacturer may decide or varying conditions or uses may demand. 1

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A combined container and syringe comprising a barrel and a soft, flexible, resilient, elastic member therewithin, said member having a forward portion, a rearward portion and an intermediate portion connecting said two first mentioned portions, the forward face of said forward portion having an annular groove therein extending through said forward portion and at least into said intermediate portion, the outer periphery of said rearward portion being. substantially smaller than the interior of said barrel to form a manipulating shank, said forward portion being normally slightly larger than said interior to form a contact portion, said contact portion having a ring of contact with the interior'of saidtact portion to that of said shank portion, all of said contact and intermediate portions being of a thickness suilicient to maintain said contact during shipment and storage and to prevent'curling back to maintain said contact on pushing said member forwardly.

2. A combined'container and syringe comprising: abarrel; and a soft, flexible, resilient, elastic plunger accommodated within said barrel, said plunger having a forward contact portion of a uniform and normally larger diameter than that of said barrel and merging into a rearwardly extending portion having a cross-sectional area somewhat smaller than that of said barrel, the forward face of said forward .contact portion having an annular groove therein extending through said forward contact portion and at least into said rearwardly extending portion, the outer wall of said groove being at all points thereof a ROBERT K. CUTTER. 

